Field of Invention
The present invention related to a dry granulator, and more particularly to a dry granulator which is tight in structure, has reliable sealing ability of the feeding mechanism, has a high granulating efficiency, can provide high quality of finished particles products, has a low fine powder rate, is able to be applied to different kinds of mobile powders, and is easy to being automation production.
Description of Related Arts
Dry granulator is applied in the production of granular products, wherein the purpose of the dry granular is used to press variety of mobile powders into particle products with a predetermined and qualified particle size. Dry granular mainly includes a loading mechanism, a feeding mechanism, a pressing mechanism, a crushing mechanism, a granulating mechanism and a sieving mechanism. Dry granulator is already provided on the market for many years, but due to various kinds technical limitations, the current dry granulator commonly has the disadvantages of having a tight-less structure, unreliable sealing abilities of feeding mechanism, low granulating efficiency, and providing low quality of finished particles products (refer to technical parameters of sheet weights, hardness, and disintegration), and also has a high fine powder rate. Therefore, the current dry granulator cannot be applied to different kinds of mobile powders, and also have a difficult for being automation production.
Accordingly, the pressing mechanism is adapted to press powder materials delivering from the feeding mechanism, wherein the pressing mechanism comprises an upper pressing wheel and a lower pressing wheel, which are rotating in a counter direction. According to the prior art, a position of the lower pressing wheel is fixed, and the upper pressing wheel is driven by two hydraulic pressure cylinders, a front hydraulic pressure cylinder and a rear pressure cylinder, to remain a radial clearance between the upper and lower pressuring wheel while the pressing mechanism is working. A disadvantage of the above mentioned pressing mechanism is that the pushing force provided by the front and the rear hydraulic pressure cylinders will not fully balance, such that a front and rear end of pressing wheel shaft will produce different degrees of abrasion. At the same time, while the hydraulic oil in the hydraulic pressure cylinder is compressed and released, a certain amount of oil gas inevitably separate out to contaminate the high quality requirement of a granulating environment. Furthermore, since an axial position of the upper and lower pressing wheel is fixed and non-adjustable, so the height between an outer face end for the upper and lower pressing wheel has a certain degree of error, when the error exceeds 0.05 mm, the powder leakage phenomenon will generate on an area between the outer face end of the upper pressing wheel, the outer face end of the lower pressing wheel, and a cover arranged on the outer face end of the pressing wheel.
Accordingly, the feeding mechanism is adapted to deliver the powder materials to the pressing mechanism. In the current dry granular, the feeding mechanism comprises a feeding cylinder and a feeding screw rotatably mounted within the feeding cylinder. In order to improve the capacity and efficiency of the transportation for the powder materials, there are two feeding screws arranged within the feeding cylinder, wherein the feeding screws are tapered screws, and a top end of each of the two feeding screws is also designed as a tapered structure. Moreover, the anti-leakage method for the feeding mechanism, which is adapted to prevent the powder materials leaking from the rear end of the feeding cylinder, is only by sealing the rear end of the feeding cylinder, but in the practical application process, the leakage problem is difficult to be solved, and especially for the good mobility materials. Therefore, the anti-leakage method is an important technical problem for the current dry granulator.
Accordingly, the sieving mechanism is adapted to separate semi-finished particles products from the fine powder (containing fine particles) and qualified particles products. Currently, the sieving mechanism for the dry granular on the current market commonly has the disadvantages of that the sieving efficiency is low, the purity of the finished particles is poor, and the fine powder rate of the finished products is high, especially in the sieving process, flying dusts will generate to cause the environmental pollution. In order to solve the above mentioned problems, a patent application No. 201320285668.6 is filed on May 23, 2013 named “sieving mechanism for dry granular”. Although, the above filed patent application is able to solve the above mentioned problems, but in the actual trial process, while the fine powders pass through meshes of the sieving tray and fall down to the powder receiving tray, the fine powder will not gather toward a center of the powder receiving tray (the fine powder will be efficiently sucked out due to a large pressure difference between an outlet adjacent to the center of the powder receiving tray), such that the fine powder will gather away from the center of the powder receiving tray. Even more, the fine powder will reversely overflow to pass through the meshes of the sieving tray to mix with the finished particles products, such that technical objectives of the present patent invention cannot be reached.
Accordingly, the crushing mechanism is adapted to granulate crushed powder sheets to produce qualified granulated particles products. Currently, the crushing mechanism for dry granular on the market includes a swing structure, a granulating wheel, and a mesh wheel structure, but all of the crushing mechanisms have the following disadvantages: poor granulating effects, high fine powder rates, and low granulating efficiency. In order to solve the above problems, a china patent application filed on May 23, 2013, having a patent application No. 201320285689.8, named “granulating mechanism for dry granular”, is already applied. Although, the patented technologies of the above China patent application is able to solve the above problems, but the structure of the granulating mechanism in the above China patent application is relatively complex. Furthermore, the designs of the granulating wheel, the screen wheel, and the screen will cause low granulating effects, high fine powder rate, and low granulating efficiency.
According to the feeding mechanism of the present invention, the pressure of a feeding inlet is large, such that if the feeding mechanism is not guaranteely sealed, the powder materials will be sprayed out. Currently, the sealing device of the feeding mechanism is adapted to install a sealing knife or swinging sealing knifes on a feeding outlet of the feeding cylinder, wherein a knife head of the sealing knife is in contact with an outer circumference of the powder sheet pressing wheel to ensure the sealing quality. However, in order to ensure the besting sealing quality, the knife head of the sealing knife must be connected with the outer circumference of the powder sheet pressing wheel to from a high precision and flat sealing line. But, in fact, it is very difficult to approach the two above mentioned sealing knife structures, wherein the sealing knife requires to be processed in high precision technology and the lifespan of the sealing knife will be reduced, and the sealing knife is very inconvenient to be assembled and disassembled.